Re: [PATCH 4/6] power: max77843_battery: Add Max77843 fuel gauge device driver

[Sebastian Reichel <sre-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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Hi,

On Fri, Jan 23, 2015 at 02:02:45PM +0900, Jaewon Kim wrote:
> From: Beomho Seo <beomho.seo-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> 
> This patch adds device driver of max77843 fuel gauge.
> The driver support for battery fuel gauge in Maxim Max77843.
> It is fuel-gauge systems for lithuum-ion batteries in handled and
> portable devices.
> 
> Cc: Sebastian Reichel <sre-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Signed-off-by: Beomho Seo <beomho.seo-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> ---
>  drivers/power/Kconfig            |    9 ++
>  drivers/power/Makefile           |    1 +
>  drivers/power/max77843_battery.c |  283 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 293 insertions(+)
>  create mode 100644 drivers/power/max77843_battery.c
> 
> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> index a054a28..0039bbb 100644
> --- a/drivers/power/Kconfig
> +++ b/drivers/power/Kconfig
> @@ -212,6 +212,15 @@ config BATTERY_MAX17042
>  	  with MAX17042. This driver also supports max17047/50 chips which are
>  	  improved version of max17042.
>  
> +config BATTERY_MAX77843
> +	tristate "Maxim MAX77843 Fuel Gauge"
> +	depends on MFD_MAX77843
> +	help
> +	  This add support for battery fuel gauge in Maxim MAX77843.

add -> adds

> +	  It is fuel-gauge systems for lithuum-ion (Li+) batteries in handled and
> +	  portable devices. The MAX17040 is configured to operate with a single
> +	  lithium cell.

It is a fuel-gauge for a lithium-ion batteries with a single
cell and can be found in portable devices.

> +
>  config BATTERY_Z2
>  	tristate "Z2 battery driver"
>  	depends on I2C && MACH_ZIPIT2
> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> index 212c6a2..ae0d795 100644
> --- a/drivers/power/Makefile
> +++ b/drivers/power/Makefile
> @@ -33,6 +33,7 @@ obj-$(CONFIG_BATTERY_DA9030)	+= da9030_battery.o
>  obj-$(CONFIG_BATTERY_DA9052)	+= da9052-battery.o
>  obj-$(CONFIG_BATTERY_MAX17040)	+= max17040_battery.o
>  obj-$(CONFIG_BATTERY_MAX17042)	+= max17042_battery.o
> +obj-$(CONFIG_BATTERY_MAX77843)	+= max77843_battery.o
>  obj-$(CONFIG_BATTERY_Z2)	+= z2_battery.o
>  obj-$(CONFIG_BATTERY_S3C_ADC)	+= s3c_adc_battery.o
>  obj-$(CONFIG_BATTERY_TWL4030_MADC)	+= twl4030_madc_battery.o
> diff --git a/drivers/power/max77843_battery.c b/drivers/power/max77843_battery.c
> new file mode 100644
> index 0000000..a08dd0c
> --- /dev/null
> +++ b/drivers/power/max77843_battery.c
> @@ -0,0 +1,283 @@
> +/*
> + * Fuel gauge driver for Maxim MAX77843
> + *
> + * Copyright (C) 2014 Samsung Electronics, Co., Ltd.
> + * Author: Beomho Seo <beomho.seo-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published bythe Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/power_supply.h>
> +#include <linux/mfd/max77843-private.h>
> +
> +struct max77843_battery {
> +	struct device		*dev;
> +	struct max77843		*max77843;
> +	struct i2c_client	*client;
> +	struct regmap		*regmap;
> +	struct power_supply	psy;
> +};
> +
> +static int max77843_battery_get_capacity(struct max77843_battery *battery)
> +{
> +	struct regmap *regmap = battery->regmap;
> +	int ret, val;
> +	u8 reg_data[2];
> +
> +	ret = regmap_bulk_read(regmap, MAX77843_FG_REG_SOCREP, reg_data, 2);
> +	if (ret) {
> +		dev_err(battery->dev, "Failed to read fuelgauge register\n");
> +		return ret;
> +	}
> +
> +	val =  ((reg_data[1] * 100) + (reg_data[0] * 100 / 256)) / 100;

so

val = reg_data[1]?

> +	return val;
> +}
> +
> +static int max77843_battery_get_energy_prop(struct max77843_battery *battery,
> +		enum power_supply_property psp)
> +{
> +	struct regmap *regmap = battery->regmap;
> +	unsigned int reg;
> +	int ret, val;
> +	u8 reg_data[2];
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_ENERGY_FULL:
> +		reg = MAX77843_FG_REG_FULLCAP;
> +		break;
> +	case POWER_SUPPLY_PROP_ENERGY_NOW:
> +		reg = MAX77843_FG_REG_REMCAP_REP;
> +		break;
> +	case POWER_SUPPLY_PROP_ENERGY_AVG:
> +		reg = MAX77843_FG_REG_REMCAP_AV;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_bulk_read(regmap, reg, reg_data, 2);
> +	if (ret) {
> +		dev_err(battery->dev, "Failed to read fuelgauge register\n");
> +		return ret;
> +	}
> +
> +	val = (reg_data[1] << 8) | reg_data[0];
> +
> +	return val;
> +}
> +
> +static int max77843_battery_get_current_prop(struct max77843_battery *battery,
> +		enum power_supply_property psp)
> +{
> +	struct regmap *regmap = battery->regmap;
> +	unsigned int reg;
> +	int ret, val;
> +	u8 reg_data[2];
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +		reg = MAX77843_FG_REG_CURRENT;
> +		break;
> +	case POWER_SUPPLY_PROP_CURRENT_AVG:
> +		reg = MAX77843_FG_REG_AVG_CURRENT;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_bulk_read(regmap, reg, reg_data, 2);
> +	if (ret) {
> +		dev_err(battery->dev, "Failed to read fuelgauge register\n");
> +		return ret;
> +	}
> +
> +	val = (reg_data[1] << 8) | reg_data[0];
> +	if (val & 0x8000) {
> +		/* Negative */
> +		val = ~val & 0xffff;
> +		val++;
> +		val *= -1;
> +	}
> +	/* Unit of current is mA */
> +	val =  val * 15625 / 100000;
> +
> +	return val;
> +}
> +
> +static int max77843_battery_get_voltage_prop(struct max77843_battery *battery,
> +		enum power_supply_property psp)
> +{
> +	struct regmap *regmap = battery->regmap;
> +	unsigned int reg;
> +	int ret, val;
> +	u8 reg_data[2];
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +		reg = MAX77843_FG_REG_VCELL;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
> +		reg = MAX77843_FG_REG_AVG_VCELL;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_OCV:
> +		reg = MAX77843_FG_REG_OCV;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_bulk_read(regmap, reg, reg_data, 2);
> +	if (ret) {
> +		dev_err(battery->dev, "Failed to read fuelgauge register\n");
> +		return ret;
> +	}
> +
> +	val = ((reg_data[1] << 4) + (reg_data[0] >> 4)) * 125;
> +	val /= 100;
> +
> +	return val;
> +}
> +
> +static const char *model_name = "MAX77843";
> +static const char *manufacturer = "Maxim Integrated";
> +
> +static int max77843_battery_get_property(struct power_supply *psy,
> +		enum power_supply_property psp,
> +		union power_supply_propval *val)
> +{
> +	struct max77843_battery *battery = container_of(psy,
> +				struct max77843_battery, psy);
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
> +	case POWER_SUPPLY_PROP_VOLTAGE_OCV:
> +		val->intval = max77843_battery_get_voltage_prop(battery, psp);
> +		break;
> +	case POWER_SUPPLY_PROP_CURRENT_NOW:
> +	case POWER_SUPPLY_PROP_CURRENT_AVG:
> +		val->intval = max77843_battery_get_current_prop(battery, psp);
> +		break;
> +	case POWER_SUPPLY_PROP_ENERGY_FULL:
> +	case POWER_SUPPLY_PROP_ENERGY_NOW:
> +	case POWER_SUPPLY_PROP_ENERGY_AVG:
> +		val->intval = max77843_battery_get_energy_prop(battery, psp);
> +		break;
> +	case POWER_SUPPLY_PROP_CAPACITY:
> +		val->intval = max77843_battery_get_capacity(battery);
> +		break;
> +	case POWER_SUPPLY_PROP_MODEL_NAME:
> +		val->strval =  model_name;
> +		break;
> +	case POWER_SUPPLY_PROP_MANUFACTURER:
> +		val->strval = manufacturer;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static enum power_supply_property max77843_battery_props[] = {
> +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
> +	POWER_SUPPLY_PROP_VOLTAGE_AVG,
> +	POWER_SUPPLY_PROP_VOLTAGE_OCV,
> +	POWER_SUPPLY_PROP_CURRENT_NOW,
> +	POWER_SUPPLY_PROP_CURRENT_AVG,
> +	POWER_SUPPLY_PROP_ENERGY_FULL,
> +	POWER_SUPPLY_PROP_ENERGY_NOW,
> +	POWER_SUPPLY_PROP_ENERGY_AVG,
> +	POWER_SUPPLY_PROP_CAPACITY,
> +	POWER_SUPPLY_PROP_MODEL_NAME,
> +	POWER_SUPPLY_PROP_MANUFACTURER,
> +};
> +
> +static const struct regmap_config max77843_fuel_regmap_config = {
> +	.reg_bits	= 8,
> +	.val_bits	= 8,
> +	.max_register	= MAX77843_FG_END,
> +};

You always read 2 bytes, so it seems the device uses 16 bit sized
values?

> +static int max77843_battery_probe(struct platform_device *pdev)
> +{
> +	struct max77843 *max77843 = dev_get_drvdata(pdev->dev.parent);
> +	struct max77843_battery *battery;
> +	int ret;
> +
> +	battery = devm_kzalloc(&pdev->dev, sizeof(*battery), GFP_KERNEL);
> +	if (!battery)
> +		return -ENOMEM;
> +
> +	battery->dev = &pdev->dev;
> +	battery->max77843 = max77843;
> +
> +	battery->client = i2c_new_dummy(max77843->i2c->adapter, I2C_ADDR_FG);
> +	if (!battery->client) {
> +		dev_err(&pdev->dev, "Failed to get dummy i2c client.\n");
> +		return PTR_ERR(battery->client);
> +	}
> +	i2c_set_clientdata(battery->client, max77843);
> +
> +	battery->regmap = devm_regmap_init_i2c(battery->client,
> +			&max77843_fuel_regmap_config);
> +	if (IS_ERR(battery->regmap)) {
> +		ret = PTR_ERR(battery->regmap);
> +		goto err_i2c;
> +	}
> +
> +	platform_set_drvdata(pdev, battery);
> +
> +	battery->psy.name	= "max77843-fuelgauge";
> +	battery->psy.type	= POWER_SUPPLY_TYPE_BATTERY;
> +	battery->psy.get_property	= max77843_battery_get_property;
> +	battery->psy.properties		= max77843_battery_props;
> +	battery->psy.num_properties	= ARRAY_SIZE(max77843_battery_props);
> +
> +	ret = power_supply_register(&pdev->dev, &battery->psy);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed  to register power supply\n");
> +		goto err_i2c;
> +	}
> +
> +	return 0;
> +
> +err_i2c:
> +	i2c_unregister_device(battery->client);

This is missing in max77843_battery_remove()

> +
> +	return ret;
> +}
> +
> +static int max77843_battery_remove(struct platform_device *pdev)
> +{
> +	struct max77843_battery *battery = platform_get_drvdata(pdev);
> +
> +	power_supply_unregister(&battery->psy);
> +
> +	return 0;
> +}

> [...]

-- Sebastian

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